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We purified and characterized an extracellular hemolysin produced by Listeria monocytogenes. Hemolysin production was greatly enhanced by growing bacteria in resin (Chelex)-treated medium. This hemolysin was separated as a homogeneous protein of 60,000 daltons by using thiol-disulfide exchange affinity chromatography. This protein was a sulfhydryl-activated(More)
The lecithinase gene of the intracellular pathogen Listeria monocytogenes, plcB, was identified in a 5,648-bp DNA fragment which expressed lecithinase activity when cloned into Escherichia coli. This fragment is located immediately downstream of the previously identified gene mpl (prtA). It contains five open reading frames, named actA, plcB, and ORFX, -Y,(More)
The Bordetella pertussis cyaA gene encodes a virulence factor which is a bifunctional protein exhibiting calmodulin-sensitive adenylate cyclase and hemolytic activities (P. Glaser, H. Sakamoto, J. Bellahov, A. Ullmann, and A. Danchin, EMBO J. 7:3997-4004, 1988). We characterized the hemolytic and toxin activities of the 200-kilodalton (kDa) bifunctional(More)
To evaluate the role of hemolysin production in the virulence of Listeria monocytogenes, we have undertaken the analysis of the chromosomal region containing hlyA, the gene coding for listeriolysin O. A recombinant cosmid, conferring a hemolytic phenotype to Escherichia coli, was shown to express listeriolysin O, by immunoblotting with a specific antiserum(More)
Purified streptococcal mitogens (SMs) including erythrogenic exotoxin were compared with phytohemagglutinin (PHA) for their ability to sustain lymphadenopathy-associated virus (LAV) replication after the stimulation of normal human peripheral blood mononuclear cells and purified CD4+ and CD8+ T cells infected with LAV. Both SM and PHA supported LAV(More)
The negative mutant approach was used in this study to identify listerial cytolytic factors involved in cooperative haemolysis (CAMP-like phenomenon) with Staphylococcus aureus and Rhodococcus equi. A Listeria monocytogenes non-haemolytic mutant specifically impaired in listeriolysin O (LLO) production gave no CAMP reaction with S. aureus, and was virtually(More)
A 68-kDa glycoprotein bearing the biological activity of the plasma membrane serotonin (5-hydroxytryptamine, 5-HT) transporter has been purified from human blood platelets, a classical cell model for the study of 5-HT uptake. After treatment of the whole platelet population or its plasma membrane fraction by sulfhydryl-dependent bacterial protein toxins or(More)
The determination of protein M and T serotypes, biotypes and pyrogenic (erythrogenic) exotoxin A (SPE A), streptolysin O (SLO), streptokinase (SK), hyaluronidase (HA) and cysteine proteinase release by 212 S. pyogenes isolates from patients with severe invasive group A streptococcal (GAS) infections, among them 74 cases of streptococcal toxic shock syndrome(More)
We purified and characterized an extracellular phospholipase produced by Listeria monocytogenes. This enzyme was separated as a homogeneous protein of 29 kDa by chromatography on DEAE-52 cellulose and Bio-Gel P100 columns. It is a zinc-dependent phospholipase C (PLC) that is mainly active at pH 6 to 7 and expresses lecithinase activity and a weaker(More)